The density of integrated circuits continues to increase and as a result, the number of delicate leads between the integrated circuit and a printed circuit board likewise increases. A difficult problem still confronting engineers in the electronics industry is an efficient and reliable way to secure an integrated circuit to a board while maintaining electrical connection and mechanical protection of the leads.
A fabrication process known in the electronics packaging art is tape automated bonding (TAB). A continuous tape of fragile conductive traces, similar to, but far more fragile than photographic film, provides a basis for mounting integrated circuits on each frame of the tape.
A metal pattern is formed on each frame of the conductive trace. These metal patterns radiate from the center of the trace where an integrated circuit is mounted to the peripheral edges of the frame to form leads. The circuit is mounted such that the contacts of the chip are mated with the corresponding metal pads in the central portion of the frame. These fragile conductive traces provide for electrical connection between the integrated circuit and the circuit board.
The manufacture of electronic components, sub-assemblies and assemblies requires a number of functionally different manufacturing operations. Manufacturing the fragile components, testing, and final assembly of the components are three different operations which are required. The complex and additive nature of these operations makes cost effective manufacturing difficult. Each operation requires unique and complicated equipment. To perform these operations is relatively expensive, and there is also a relatively high possibility for defects.
U.S. Pat. No. 5,099,392, entitled "Tape-Automated Bonding Frame Adapter System" and issued to the Hewlett-Packard company on Mar. 24, 1992, illustrates an adapter system for mounting an integrated circuit and conductive trace to a circuit board. This adapter system comprises three separate components to mount the frame to a circuit board by building a sandwich of parts. An adapter ring is positioned on the circuit board. A plurality of conductive elements are wrapped around members of the adapter ring to provide electrical connection between the circuit board and conductive trace. The conductive trace is mounted over the adapter ring. A seal is mounted over the conductive trace and finally a lid is provided over the entire assembly to protect the conductive trace. The entire assembly is secured in place by a number of fasteners (e.g., nuts and bolts).
U.S. Pat. No. 4,696,526, entitled "Carrier for Tape Automated Bonded Semiconductor Device" and issued to the Intel Corporation on Sep. 29, 1987, illustrates a device for mounting an integrated circuit and conductive trace to a base for electrical test of the integrated circuit. This device comprises two separate and complicated components to mount a conductive trace by building a sandwich of parts. A base is provided with a socket for receiving the trace. The trace is positioned within the base by a plurality of lugs. A cover is placed over the trace and locked in place with the base by a number of complimentary locking members.
U.S. Pat. No. 5,005,070, entitled "Soldering Interconnect Method and Apparatus For Semiconductor Packages" and issued to the Hewlett-Packard company on Apr. 2 1991, illustrates a device for attaching the outer leads of a semiconductor package to lands on a circuit board. This device comprises a frame structure that urges the edges of a semiconductor package to the board. The frame structure is secured in position either adhesively, or by the thermal deformation of stakes.
IBM Technical Disclosure Bulletin Vol. 34, No. 11 of April, 1992, pp. 234-236 and entitled, "Method of Bonding Tape Automated Bonding Packages Using Conventional Surface Mount Technologies", illustrates a temporary fixture that may be used in the assembly of a circuit module with a printed circuit board. The fixture temporarily grips the module in order to transport and place the module on a printed circuit board. After a solder process, the fixture releases the module and is removed for recycling, leaving the unprotected module behind. The circuit module is relatively thick and durable compared to the circuit trace contemplated herein.
The structures illustrated in the above documents have a number of significant deficiencies. Most systems have multiple components which are costly to manufacture. Aligning a sandwich of components on a circuit board is difficult, costly and time consuming. Such alignment is also prone to error.
Retention of a fragile conductive trace having an integrated circuit and retention on a circuit board in a unitary protective structure is not disclosed in the above documents. Typically, conductive traces having integrated circuits are stored and shipped separately from the mounting devices. Separate storing of the unprotected conductive traces is difficult due to the fragile nature of the traces and integrated circuits. This typically requires additional protective packaging for storage and shipping of components.
It is believed that an electronic package, clamp for use therewith and method for providing such a package which overcomes the aforementioned problems while assuring protection in the manner cited below would constitute a significant advancement in the art.